1. Field of the Invention
The present invention relates to a memory control apparatus and method for digital signal processing. More particularly, the present invention relates to a system and method for operating a plurality of digital signal processors using one memory card.
2. Description of the Related Art
Generally, a digital signal processor (DSP) is used for real-time processing of a digital signal. The digital signal typically includes data representing a serial number or a digital value for indicating a corresponding analog signal. DSPs are used in diverse fields such as, for example, audio systems such as a small-sized disc player, radio communication systems such as a cellular phone, digital still cameras (DSC), and digital video cameras (DVC).
Recently, with the demand for combined appliances, the development of a dual appliance having two or more functions has increased remarkably. In particular, techniques for integrating a DVC for taking a moving image and a DSC for recording a still image into one appliance have been used significantly.
A conventional technique of integrating the DSC and DVC is illustrated in FIGS. 1 and 2. FIG. 1 is a perspective view of an apparatus for taking an image in which a digital still camera and a digital video camera are integrated. FIG. 2 is a block diagram of the apparatus illustrated in FIG. 1. Referring to FIGS. 1 and 2, the body 10 of the apparatus includes a DSC signal conversion unit 40, a DVC signal conversion unit 45, a still image codec unit 50, a moving image codec unit 65, a storage unit 60, an input unit 70, a display unit 80, and a control unit 90.
A camera part 20 includes a housing 15 rotatably installed on the body 10, a first camera 22 for taking a still image, and a second camera 24 for taking a moving image. The first camera 22 and the second camera 24 are arranged to face each other.
Accordingly, the camera part 20 rotates clockwise or counterclockwise at a predetermined angle on an rotating axis X, and it is preferable that the camera part 20 rotates to the extent that a DSC lens group 22a and a DVC lens group 24a maintain balance with an image-taking direction A. That is, as shown in FIG. 2, it is preferable that, if the housing 15 is manually rotated at an angle of 180° , the positions of the DSC lens group 22a and the DVC lens group 24a alternate directions in which they face.
The first camera 22 has a DSC lens group 22a, a DSC driving unit 22b, a DSC detection unit 22c, and a DSC image pickup unit 22d. The DSC lens group 22a is for taking a still image, and the DSC driving unit 22b moves a DSC zoom lens (not illustrated) and a DSC focus lens (not illustrated) under control of the control unit 90. The DSC detection unit 22c is a sensor for detecting the position of a lens under the control of control unit 90, and the DSC image pickup unit 22d converts the image signal of an object that has passed through the DSC zoom lens (not illustrated) and the DSC focus lens (not illustrated) into an electric image signal using a charge coupled device or any other suitable component.
The second camera 24 has a DVC lens group 24a, a DVC driving unit 24b, a DVC detection unit 24c, and a DVC image pickup unit 24d. Its operation is the same as that of the first camera 22.
The DSC signal conversion unit 40 and the DVC signal conversion unit 45 remove noise included in electric signals output from the DSC image pickup unit 22d and the DVC image pickup unit 24c, and amplify gains so that the converted electric image signals are output with a constant or a substantially constant level. Also, the DSC signal conversion unit 40 and the DVC signal conversion unit 45 convert the electric analog signals into digital image signals, and output automatic control data through digital processing.
The still image codec unit 50, under control of the control unit 90, compresses the still image signal output from the DSC signal conversion unit 40 using a compression system such as JPEG. The compressed still image data is stored in a storage medium, such as flash memory 62, of the storage unit 60.
The moving image codec unit 65, under control of the control unit 90, compresses the moving image signal output from the DVC signal conversion unit 45 using a compression system such as JPEG. The compressed moving image data is stored in a storage medium, such as tape 64, of the storage unit 60.
If a reproduction command signal for reproducing the stored image signal is input through the input unit 70, the still image codec unit 50 and the moving image codec unit 65 discontinue compression of the coded data stored in the flash memory 62 and tape 64, respectively, under control of the control unit 90.
For example, if a reproduction command signal for reproducing the still image signal is input through the input unit 70, the still image codec unit 50 discontinues the compression of the coded still image data stored in the flash memory 62, and outputs the still image data to the display unit 80.
The input unit 70 has an image-taking key 70a for providing an image-taking command signal to the control unit 90, and a plurality of manipulation buttons (not illustrated) for performing a plurality of functions. The display unit 80 has a viewfinder 82, and/or an LCD panel 84, provided on one side of the main body 10. The display unit 80 displays the image taken through the DSC 22 or DVC 24 or the compression-released image under control of the control unit 90.
The control unit 90 controls the entire operation of the image-taking apparatus using various kinds of control programs stored in the storage unit 60 and the automatic control data output from the DSC signal conversion unit 40 or the DVC signal conversion unit 45. The control unit 90 ascertains the selected image-taking mode by an output signal of a mode sensing unit 30, and drives the camera part 20 corresponding to the selected image-taking mode. For example, if signals that indicate an ON state of the DSC 22 and an OFF state of the DVC 24 are input from the mode sensing unit 30, the control unit 90 ascertains that the image-taking mode of the camera part 20 is the still image mode. Also, if the image-taking command signal is applied from the image-taking key 70a, the control unit 90 drives the DSC 22 corresponding to the still image mode. If a record command signal is applied from the input unit 70, the control unit 90 controls the still image codec unit 50 to compress the image signal of the object; if a reproduction command signal is applied, the control unit 90 controls the still image codec unit 50 to discontinue the compression of the image signal, and then displays the image signal on the display unit 80.
As described above, the DSC and the DVC have memories for storing image information and in the case of integrating the two appliances, the size of the digital camera is increased, and the operating system for controlling the respective systems is complicated.